Coaster brake



Patented Aug. 8, 1950 UNITED.;STATES PATENT oFFIcE i '.2,517,847

t a @ASTER BRAKE y .Y Theodore K. rorslsiand, Minneapolis, Minn. Application December 27, 1948, Serial No. 67,418

My invention relates :to coaster brakes 'ffor bicycles and has for an object to provideaicoaster brake in which friction is reduced-t a* minimum during pedaling ofthe bicycle. J

Another object' of -'the invention resides in.I i

providing a coaster brake in which the usualfdrag spring is eliminated. i i

A still further object of the invention'resides in constructing theU coaster brake' withfa 'clutch member and with 'a 'brakefdisccarrier :and in mounting said parts for rotation'as a unit;

A still further'` object ofthe inventionrresides in arranging the"clutch"member."and vdisccar rier 'for limited relative 'axial movement andin further providing stop means'ffor I' limiting :the movement of said'parts away lfrom oneanother."

Another object of the invention4 resides in providing a spline between "said clutch'fm'ember and carrier and -in further'providing.resilientmeans urging the clutch member and disci carrier apart.

An Vobject of the invention residesin providing' a brake' anchor xed relative'to the wheelaxle and in -providing 'locking `means between' said brake anchor and disc carrier.

A'still furtherobject of theinventio'nnresides in providing the coasterbrakewith-'a'driver hav'- ing helical threads thereon' andfsaidclutch mem; ber with a nut for engagement with said threads and iny further constructing said 'looking 'means with meshing teeth' said teeth beingl provided with helical surfaces Yhaving thel same hand and lead as the hand and lead of saidthreads.

Other objects* ofthe 'invention'fresidein f the novel combination''and,arrangementvv of 'parts and in the details of construction hereinafter illustrated, and/or described. l

In the drawingsz-v Fig. 1 is a plan` sectional view-drawnto an enlarged scale of the rear wheel-hub Aassemblyy of a bicycle taken Vat'ftheaxis offthe axle and illustrating a coasterbrake embodying'my'i'nven lon. fr, fw

Fig. 2 is a View similar to Fig. parts in alteredrrelation. ci'

Fig. 3 is a 'sectional view-.takenon `line 3-3 of Fig. 1.

Figui is a perspective View of the' partso'fthe hub assembly detached from' one another' and with parts broken' away and'withother parts shown in section. f f f Fig. 5 is a view similar '.to Figi Lli-oi.'o'tl'ier parts fQr the rear, wheel-pf; a' "bicycle, vanda/nich isi :showing the.Y

illias viewedin'lFig. 1- i`s a'brake anchor I9y in the form of a'bal'l bearing cne which is formed with fa ballr'ac'e 2l 'facing therace I'I. In these races are balls' '22 which lsupport one endl oi the iiub` iiorfrotation. `'The brakean'chor I9 functions in 'a 'mannerf to be presently described and' has secured'todtthe usualbrake arm 23 'which is'attached in the yusualmanner toV the bicycle frame. A locknutiliscrew'ed onthethreads I2 of 'axle II holds the parts,k assembled. A guard ilis clamped between the brake arm 23 and the brake anchor IQ' andl keeps "dirt out of the ball" bearing 'formed bythe balls 22 and theball racesy Iland2I'.-j.w.,.

Rotatably mounted on the intermediate portionf26 of axlell is azolriverl.' This driver" has" avballra'ce iii which faces the ballrace I8. In these'l races .are .balls j'elbwhich rotatably support the otherend foi the hub-I. itself` supported` for rotation relative tothe axle I I by means of balls 3l whichv are received in ball races 32 and 33 -formed'respectively in the driver'A 2 and in" a ball .cone 34 screwed on the threads I3'of axle I L The driver 2i' has secured to it a' sprocket wheel 35A which is screwed on the threads -'fformed on' saidldriver. This sprocket wheel -isheldin'place ouwe-driver 2 by means' of a lock nut 3l which is screwed ori-other threads 38 on said driver" and t preferably of av hand opposite the han'd'ei thethreads 36. lAguarf 3911s clamped'betw'een--the 'sprocketwheei 35 and the-driver 2l and prevents dirt. iromentering theball rbearing formed by theballs 29 and the races I8 and .28.

and 33.'

The-brake ymechanism of' the invention is "of thedisc type and includes a brake disc carrier 32. This carrier `vlis 'rotatably 'and' slidably mounted on the portiony 26 ofaXle Il' and :comprises a tubular portion 43 vwith a collar 44 'issuing outwardly therefr'om.nv The 'tubular v pcrtion iB hasijtwo flats 45. formed thereonand which',

The" driver 2IA is:

In a similar manner` a ang'e 4I formed on the'nut 3'! forms a guard for the ball bearing formedbythe ballsy 3| fand the races 32" extend parallel to the axis of the axle II. Mounted on the tubular portion 43 are discs 46 and 41 which are arranged in alternation thereon. The discs 46 have openings 48 in the centers oi the same which just t the contour of the tubular.l

portion 43. These discs are held from rotation by means of the flats 45 but may move axially along said tubular portion and are hence splined to the disc carrier. The diameter of the discs 46 is slightly less than the diameter of the bore 29 of hub I4 so that said discs may rotate freely relative thereto. The discs 48 have circular holes 49 in the same which support said discs for free rotation on the circular parts of the tubular portion 43 of disc carrier 42. These discs are of the same diameter as the discs 46 but have keys I formed thereon which are received in key ways 52 formed in the hub I4 and which extend along the bore 26. These keys may slide along the keyways 52 and are thus splined to said hub. The end disc which in the arrangement shown happens to be one of the discs 46 is adapted to butt up against a shoulder 53 formedv on the collar 44.

The clutch mechanism of the invention is indicated at 50 and comprises a movable clutch member 54 having a sleeve 55 which encircles the axle Il and a neck 61 formed on the driver 21. This sleeve has a conical clutch element 56 at the right hand end thereof as viewed in Fig. 1, which is adapted to engage a complemental clutch element 51 formed in the hub I4 at the end ofthe bore 29 therein. The surfaces of these clutch elements may be made serrated if desired to increase the holding power of the clutch 50.

Extending inwardly from the sleeve 55 is a ange 58 having a central hole 59 therein of the same size and shape as the hole 48 in clutch disc 46. The end of the tubular portion 43 is adapted to extend through this hole and by means of this construction the sleeve 55 is splined to the disc carrier 42. The sleeve 55 is restrained from axial movement away from the disc carrier 42 by means of a stop 6I. This stop is in the form of a split ring which is adapted to be snapped into a shallow annular groove 62 formed in the end of the tubular portion 43 of disc carrier 42. Within the interior of the sleeve 55 is mounted a conical compression coil spring` 63 which is seated at one end against a shoulder B4 formed in the clutch member 54 and at its other end against the end 65 of the tubular portion 43. This spring urges the flange 58 against stop 6I moving the clutch member 54 and the carrier 42 apart. 'Ihe flange 58 has a surface 66 which forms a shoulder adapted to engage the endmost disc and clamp the discs against the shoulder 53 to effect braking, when the clutch member 54 is moved toward the left as shown in Fig. 2.

For procuring relative axial movement of the clutch member 54 the neck 61 of driver 21 is constructed with helical threads 68 which are adapted to engage internal threads 69 on the clutch member 54 and which form a nut indicated in its entirety by the reference numeral 1 I. The threads 68 and 69 have a fairly great lead so that an appreciable movement of the clutch member 54 is procured upon turning of the driver 21.

In order to resist rotation of the disc carrier 42 during braking, a locking device 12 is employed. This locking device includes axially extending teeth 13 arranged circularly about the axle Il and formed on the inner end 14 of the brake anchor I9. These teeth are adapted to engage similar teeth formed on the` collar 44.

The teeth 14 and 15 have helical surfaces 16 and 11 which have the same hand and lead as the hand and lead of the threads 68 and 69. The said teeth also have surfaces 18 and 19 which lie in planes containing the axis of the axle II.

The invention operates in the following manner. A certain amount of drag exists between the discs 46 and 41 tending to make the clutch member 54 travel with the hub I4. If the driver 21 is urged to move in a direction tending to procure forward propulsion of the bicycle, threads 68 screw into nut 1I and move the clutch member to the right as viewed in Fig. l, and the clutch element 56 into engagement with the clutch element 51. At such time the teeth 13 are out of engagement with teeth 15 as seen in Fig. 1. Pedaling may now be engaged in, in the customary manner with the result of forward propulsion of the bicycle. It will be noted that since the clutch member 54 is splined to the disc carrier 42 that these parts rotate as a unit. Since the clutch elementy 56 is engaged with the clutch element 51, the hub I4, driver 21, clutch member: 54, disc carrier 42 and allof. the discs 46 and 41 rotate together and without relative movement. Hence while'pedaling there is no drag between the brake discs or drag from any drag spring and the only resistance to forwardl propulsion is the friction in the various ball bearings. Ifl the driver 21 is stopped for the purpose of coasting, the clutch 50 being in engagement, clutch member 54 continues to rotate with hub I4. There is nowy relative rotation between the nut 1I and threads 68 and the clutch 56 is positively thrown out of engagement. As soon as the clutch element 5S leaves the clutch element 51 the drag between the discs 46 and 41 again tends to cause the clutch member 54 to rotate with the hub I4. Clutch member 54 and disc carrier 42 hence continue axial movement away from the clutch element 51 until the teeth 15 mesh: with teeth 13. Due to the fact that the teeth of the locking device have surfaces with the same hand and lead as the hand and lead of the threads 68 and B9 the teeth slide easily into engagement and without attrition between the'- teeth. The disc carrier 42 and the clutch member 54 now stop and since both the brake anchor Band the driver?7 are stationary the disc carrier and clutch member also remain stationary with the locking device 12 engaged. Discs 41 now rotate relative to discs 46 but only the normal drag producedwhen the brake is disengaged is present. If the driver 21 is thrown in reverse, threads 68 further act on the nut 1I and' urge-the clutch member further toward the brake anchor I9. Disc carrier 42 due to engagement of the locking device 12 can move no further and flange 58 now moves relative to carrier 42 against the action offspring 63v and is brought into engagement with `the juxtaposed disc, clamping the discs together between the shoulders 53 and 58. Since the disc carrier 42 is restrained from movement by means of the locking device 12, braking is effected. In shifting from braking to coasting and from coasting to pedaling the procedure is reversed.

The advantages of my invention are manifest. When pedaling no drag of any kind is present except the friction produced by the bearings. The brake discs travel together and with the hub when pedaling so that no unnecessary wear on the brake discs occurs. Since the locking device becomes effective during coasting and when the clutch is disengaged no appreciable wear on they teethathereofresults. My improved coaster brake may be constructed at no greater cost than other coaster brakesnot having the advantages of my invention. Take up for wear on the brake discs becomes unnecessary with my invention. The clutch member and brake assembly may be installed and removed as a unit and by employing a special brake anchor may be substituted for the conventional clutch and brake elements.

Having described my invention what I claim as new and desire to protect by Letters Patent is:

1. In a coaster brake an axle, a hub encircling said axle and rotatable relative thereto, a brake anchor at one end of said hub, a clutch element on said hub at the other end thereof, a driver rotatable relative to said axle and disposed at the said other end of said hub, threads on said driver, a brake disc carrier axially movable and rotatable relative to said axle, brake discs on said carrier, acting between said carrier and hub, locking means between said disc carrier and brake anchor, engageable upon axial movement of the brake carrier toward said lbrake anchor, a clutch member encircling said axle and disposed between said driver and brake dise carrier and adapted to engage the clutch element on said rlhub upon axial movement away from said brake I anchor, a nut on said clutch member engageable with the threads on said driver and adapted to move axially upon relative rotation between said threads and nut, a shoulder on said brake carrier adapted to resist pressure on said discs when said locking means is engaged, a shoulder on said clutch member adapted to exert pressure on said discs when the clutch member is moved toward said brake anchor, withdrawing means acting between said clutch member and brake disc carrier for moving said carrier away from said anchor and disengaging said locking means upon movement of said clutch member into clutch engaging position, resilient means acting between said carrier and clutch member and urging said shoulders apart to free said brake discs and stop means between said clutch member and carrier limiting movement of said shoulders away from one another and causing said clutch member and carrier to move axially relative to said axle as a unit to rst bring said locking means into engagement and thereafter clamp the brake discs between said shoulders upon relative rotation oi' said nut and driver in one direction.

2. In a coaster brake an axle, a hub encircling said axle and rotatable relative thereto, a brake anchor at one end of said hub, a clutch element on said hub at the other end thereof, a driver rotatable relative to said axle and disposed at the said other end of said hub, threads on said driver, a brake disc carrier axially movable and rotatable relative to said axle, said carrier having a tubular portion and a collar at the end thereof adjacent said anchor,` brake discs on said tubular portion acting between said carrier and hub, locking means between said collar and anchor engageable upon axial movement of said disc carrier toward said anchor, a sleeve encircling saidthreads and the end of said tubular portion, a clutch element on said sleeve at one end thereof engageable with the clutch element on said hub, threads on said sleeve forming a nut engageable with the threads on said driver, a ange on said sleeve at the end thereof opposite said clutch element and extending inwardly toward said tubular portion, stop means on said tubular portion for engagement with said flange to limit axial movement of said sleeve away from said brake disc support said sleeve upon rotation of said driver in one direction relative thereto urging said ilange toward said collar and clamping said brake discs therebetween to set the brake and resilient means resisting movement of the ange toward the collar and urging the flange into engagement with said stop means.

3. In a coaster brake an axle, a hub encircling said axle and rotatable relative thereto, a brake anchor at one end of said hub, a clutch element on said hub at the other end thereof, a driver rotatable relative to said axle and disposed at the said other end of said hub, threads on said driver, a brake disc carrier axially movable and rotatable relative to said axle, said carrier having a tubular portion and a collar at the end thereof adjacent said anchor, brake discs on said tubular portion acting between said carrier and hub, locking means between said collar and anchor engageable upon axial movement of said 'disc carrier toward said anchor, a sleeve encircling said threads and the end of said tubular portion, a clutch element on said sleeve at one end thereof engageable with the clutch element on said hub, threads on said sleeve forming a nut engageable with the threads on said driver, a flange on said sleeve at the end thereof opposite said clutch element and extending inwardly toward said tubular portion, stop means on said tubular portion for engagement with said ilange to limit axial movement of said sleeve away from said brake disc support, said sleeve upon rotation of said driver in one direction relative thereto urging said ange toward said collar and clamping said brake discs therebetween to set the brake, said sleeve having an internal shoulder facing said ange, and a compression coil spring within said sleeve seated at one end against said shoulder and at its other end against a ipart restrained from axial movement relative to said disc carrier to urge said flange against said stop means.

TI-IEODORE K. CROSSLAND.

REFERENCES CITED UNITED STATES PATENTS Name Date Glacy Aug. 31. 1937 Number 

